A veritable bevy of Republican presidential hopefuls have already hired staff, wooed deep-pocketed contributors and made speeches in Iowa and New Hampshire, proving what we already know: The 2016 nomination preseason is well underway.

Fundraising, organization, the size of the field and the calendar all will play a significant role in affecting how the race unfolds. The outcome is uncertain.

The current conventional wisdom is, in spite of changes intended to shorten the nominating process, the race for the GOP nomination could be more of a marathon than a sprint.

The last two Republican presidential nominating fights — with John McCain coming back from the political grave in 2008 and Santorum ending up as Romney’s final adversary — proved the race isn’t over until it is over, and that should encourage hopefuls to remain in the hunt even after their prospects have dimmed.

Still, not everyone who runs this cycle will have the wherewithal to remain a serious contender for the party’s nomination after the first couple of contests. Former Florida Gov. Jeb Bush and Kentucky Sen. Rand Paul are the two candidates who unquestionably have staying power.

Bush, with unrivaled fundraising strength and legions of supporters who have built up loyalty to his family, looks like an overwhelming favorite to lock down the “establishment” lane in the Republican contest.

But if the former governor’s campaign will be awash in money, it’s equally true his support among primary voters and caucus attendees will be much shallower. Movement conservatives in the GOP are unlikely to embrace him any time before the general election kicks off, and that gives others in the race an opening.

Paul, who also should raise plenty of cash and has a passionate and loyal following, will generate excitement from libertarians and those who distrust the party’s political establishment. That gives him a distinct lane in the GOP race.

But while the Kentuckian's supporters will be determined and indefatigable, his foreign policy/defense agenda and record, as well as his overall libertarian approach, will turn off many mainstream Republicans.

Florida Sen. Marco Rubio and Wisconsin Gov. Scott Walker also likely will have the resources to wage serious campaigns during the nominating process, and they both have potential appeal to a wide swath of the party. That not only makes them intriguing contenders in the early nominating states, but also potentially interesting second choices to voters whose preferred candidates no longer are competitive.

Rubio is an excellent speaker with a compelling personal perspective, while Walker, a Midwest governor who took on and defeated the state’s public employee unions, has benefited from an early boomlet. They each have some appeal to both establishment and anti-establishment voters.

Louisiana Gov. Bobby Jindal, New Jersey Gov. Chris Christie, former Texas Gov. Rick Perry and Texas Sen. Ted Cruz must prove they can raise the resources to compete — not with Bush, who is widely expected to blow the rest of the field away when he reports first-quarter fundraising numbers, but with Rubio and Walker.

Jindal is trying to galvanize support on his party’s right, and he could emerge as the evangelical/social conservative/movement conservative alternative in the race. But he has lots of competition in that lane (particularly from Perry, Cruz, Ben Carson and former Pennsylvania Sen. Rick Santorum), and, like Cruz, Jindal’s outspokenness on a panoply of issues raises questions about the ultimate breadth of his appeal.

Christie’s prospects appear to have been seriously hurt by Bush’s entry into the race.

Obviously, four early GOP caucuses and primaries in Iowa, New Hampshire, Nevada and South Carolina will get a disproportionate amount of media attention, elevating their importance in the selection process.

Iowa, won by Santorum in 2012 and Mike Huckabee in 2008, clearly is favorable territory for the evangelicals and social conservative hopefuls. But the large field creates an opportunity for Bush.

Romney attracted 25 percent of the vote in each of the last two Iowa GOP caucuses, suggesting the former Florida governor can “win” the caucuses if the field is heavily fractured and conservative caucus attendees never coalesce around one or two alternatives to Bush.

Culturally and ideologically, New Hampshire would appear to be better territory for Bush. But the state hasn’t always performed well for candidates with his last name. George Bush won the primary in 1988 and 1992, but underperformed both times, and George W. Bush lost the Granite State’s primary to McCain in 2000.

The Nevada caucuses seem tailor-made for Paul, while South Carolina currently looks wide open and surely will be affected by the results of earlier contests.

Worth noting: If Bush and Rubio survive the first month of the contest, they could meet in Florida on March 1, in what would seem to be a must-win fight for both men.

The Republican presidential field will include entries from a number of party constituencies. Not everyone will have the financial resources or the potential breadth of support to be nominated, but their presence in the race could well influence primary outcomes.

The filtering process is always important in a presidential race. What makes things particularly interesting this year is the large number of contenders, the numerous factions in the GOP and the uncertainty of the outcome.